Match a Tub-Spout Shower Diverter by Connection and Pipe Projection

If you pull a knob on the tub spout to start the shower, identify the spout and its pipe connection first. A replacement mixing cartridge is not the same repair. The important replacement clues are the spout model, connection type, required adapter and pipe projection from the finished wall—not just the finish or visible length.

This guide focuses on tub-spout diverters. If you operate a wall selector, use the guide to identify the right diverter for a shower valve. For a selector at the showerhead, follow the showerhead-and-handheld compatibility checks. Shower Parts Store is an identification reference, not a parts retailer.

1. Confirm how the spout diverts water

Moen describes its lift-rod spouts as switching flow between the tub spout and showerhead. But a missing top knob does not prove a spout is non-diverting: Delta’s RP17453 diverts when you pull down at the outlet. See Moen’s spout identification guide and Delta’s RP17453 description.

Photograph the spout from the side and underneath, including any screw, brand mark or number. Record its overall length and reach into the tub.

Stop point: If you cannot tell which control redirects the water, photograph the entire setup and record what each control does before buying anything.

2. Check when—and where—the unwanted water appears

Tub water continues while the shower is selected

A substantial stream from the spout, especially with weak shower flow, makes the spout diverter a reasonable component to inspect. It does not identify a replacement part by itself.

Do not treat every small drip as failure. Kohler says its Rite-Temp systems permit a small amount of spout discharge while diverted to the shower. That is model-family guidance, not a universal allowance for every shower. Compare the behavior with the manufacturer’s troubleshooting instructions.

The shower runs while you are filling the tub

This is a different symptom: often called stacking or shower rise. Moen identifies restrictions and installation problems as possible causes, including an obstructed spout, restrictive fittings, unsuitable tub-drop piping or an incorrectly oriented valve.

Moen’s diagnostic test is to remove the spout and run water from the exposed pipe. If the unintended shower flow stops, investigate the spout; if it continues, investigate the installation rather than repeatedly replacing diverters. Only attempt this after confirming the removal method and that the exposed pipe will discharge safely into the tub. Shut off the supply for removal, then restore it for the test. Follow Moen’s stacking diagnosis.

Do not apply another brand’s pipe-spacing dimensions to your valve. Use the installation instructions for the actual model.

Water keeps dripping after the main control is off

Separate brief drainage from ongoing leakage. Kohler’s Rite-Temp guidance distinguishes residual water draining from the showerhead from a continuing valve leak; the latter can require the correct mixer-cap and pressure-balancing-unit repair, not a spout diverter. See Kohler’s leak diagnosis.

Stop point: Water emerging at the wall connection, a moving pipe or suspected concealed leakage needs investigation before a cosmetic spout replacement.

3. Identify the connection before removal

For Moen spouts, a visible underside set screw identifies a CC/slip-fit connection; its IPS/threaded spouts have no such screw. Keep that rule within its documented scope: other designs use adapters. Moen’s guide explains the distinction.

Before disassembly, shut off the water supply and open the control to verify that flow has stopped and relieve pressure. Moen also requires supply shutoff before servicing a spout diverter gate.

For the Moen connections described above, the threaded spout unthreads counterclockwise; the slip-fit spout slides off after its set screw is loosened. Do not twist a slip-fit spout as though it were threaded. Follow Moen’s removal instructions only after confirming the connection. Stop if removal starts turning or bending the pipe rather than releasing the part.

After safe removal, record:

• Pipe or adapter type: smooth copper, threaded nipple or a separate adapter.
• Projection: distance from the finished wall—not the backing board—to the pipe end and relevant adapter features.
• Connection dimensions: measured outside diameter, thread specification where applicable, and thread location.
• Condition: burrs, corrosion, damaged threads or damaged sealing surfaces.

Then compare those observations with the replacement’s installation drawing. Matching the visible spout length is not enough.

For example, Delta lists RP17453 as a 5¼-inch pull-down spout for sweating onto ½-inch copper water tube or threading onto ½-inch IPS. Its installation sheet groups it with the RP12307 sweat/thread-on adapter. The same sheet covers other spouts using different adapters or direct slip-on connections. A shared nominal pipe size does not make those arrangements interchangeable. Check Delta’s product details and the model-specific section of its installation sheet.

4. Decide whether to order a kit or a complete spout

Use the manufacturer’s parts diagram to determine whether it specifies a serviceable diverter kit or replacement of the complete spout. Moen, for example, publishes instructions for a replaceable diverter gate kit, but that does not establish compatibility with every spout. Match the listed part number; do not order a loose gate or seal solely because it looks similar.

Your ordering record should contain the confirmed model or replacement part number, connection type, measured projection, required adapter and finish. If any fit-critical item remains unknown, keep the photographs and measurements together and ask the manufacturer to confirm the match before ordering.